Light unit



Dec. 17, 1957 w. A. PENNOW LIGHT UNIT 4 Sheets-Sheet 1 Original Filed Aug. 7, 1947 fir;

I 4 I r i v i I vv lNVENTOR Willis A. Pennow. 5

WITNESSES ATTORNEY Dec. 17, 1957 w. A. PENNOW LIGHT UNIT Original Filed Aug. '7, 1947 Fig.2

4 Sheets-Sheet 2 Door Switch Dec. 17, 1957 w. A. PENNOW LIGHT UNIT 4 Sheets-Sheet 3 Original Filed Aug. 7, 1947 RFI TFI

m 0 II w) 8 0 6 4 at. z w m L 4 4 2 a 1 llllllll I M a I F V LIGHT UNIT 4 Sheets-Sheet 4 Original Filed Aug. '7, 1947 Uited States Pate ntO LIGHT UNIT Willis A. Pennow, Cleveland, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Original application August 7, 1947, Serial No. 767,137. Divided and this application August 31, 1954, Serial No. 453,246

11 Claims. (Cl. 340-25) My invention relates, generally, to lighting equipment, and, more particularly, to lighting equipment for use as an aid in landing aircraft. I

Due to the increase in air traflic in recent years, there has been an increasing demand for apparatus whereby an aircraft may he landed during adverse weather conditions. With such apparatus, it is obvious that the landing delays and detained flights, etc. would be minimized. Heretofore, lighting units for such purposes have been limited to moderate energy consumption, whereby the brightness output of the unit is limited. Some of such prior units have been limited in brightness by the size of the capacitor and the voltage output of the wiring means. In many approach lighting systems, it is also highly desirable to be able to flash the light units in a predetermined manner which may be varied as the weather conditions change. Some prior units have provided means for selectively obtaining such flashing, but have not provided any means whereby the intensity of the flash may be varied. Such units which have been flashed have also required an extensive control system which is not adapted to be used in a large'multiple unit installation in view of the cost of the control system. Nor have such units been adapted to be'flashed at difierent intensities in view of the additional wiring costs that would be required.

Accordingly, one object of my invention is to provide a new and improved airport approach lighting unit.

Another object of my invention is to provide a new and improved lighting unit which may be operated continuously or at various selectable intensities.

Another object of my invention is to provide a new and improved lighting unit which may be flashed at various selectable intensities. i

Still another object of my invention is to provide a new and improved lighting unit which is adapted to. be used with a number of other units, all of which are adapted to be energized from a single source of power.

A further object of my invention is to provide a new and improved airport lighting unit which is provided with an individual power unit within the housing of the unit.

These and other objects of my invention will become more apparent upon consideration of the following detailed description of a preferred embodiment thereof when taken in connection with the attached drawings, in which:

Figure 1 is a substantially central vertical cross-sectional view of one type of lighting unit constructed in accordance with the principles of my invention with the wiring removed and with portions shown in elevation;

Fig. 2 is a substantially central vertical cross-sectional view of another type of lighting unit constructed in accordance with the principles of my invention;

Fig. 3 is a reduced front elevational view of the lighting unit shown in Fig. 1 with the front door removedtherefrom; 1

Fig. 4 is a wiring diagram for the lighting unit as shown in Fig. 1;

Fig. 5 is a reduced front elevational view of the light- 2,81 7 ,5 9 Patented Dec. 1 7, 1 $57 ICC ing unit shown in Fig. 2 with the front door removed therefrom; and

Fig. 6 is a wiring diagram of the lighting unit shown in Fig. 2.

As has been indicated, the lighting units constructed in accordance with the principles of my invention are particularly adapted for use in airplane approach lighting systems as is more fully described and claimed in my copending application, Serial No. 767,137, filed August 7, 1947, now issued as Patent No. 2,734,180, on an Approach Light System, which has been assigned to the same assignee as this invention, and of which this application is a division. It is obvious, however, that these units are equally suitable for other types of applications, wherein a high degree of control of high intensity light is desired.

Primarily, it will be noted from the drawings that there are two basic types of lighting units constructed in accordance with the principles of my invention, which, for convenience in discussion, will be referred to as flash and blaze units. The unit and wiring diagram relating to a flash unit is shown in Figs. 1, 3 and 4, and the unit and wiring diagram relating to a blaze unit is shown in Figs. 2, 5 and 6. Such terminology is for convenience in describing the units and should not be considered as limiting; particularly so, in view of the fact that the blaze unit may be utilized to operate as a flashing unit.

Referring to Fig. 1, it will be noted that the flash unit comprises an open-ended housing 2 having an approximately rectangular cross-section which is provided with an integral downwardly extending conical shaped base 3 whereby housing 2 may be supported by means of a ball joint 8. Housing 2 may be made from a variety of materials having suflicient mechanical strength and is preferably formed from a material, which, in view of the size, may easily be cast to the desired shape. In view of the excellent resistance to corrosion and light weight, housing 2 is preferably formed from an aluminum casting alloy as is commercially available. Each open end of housing 2 is provided with an integral lip 4- around its periphery. An approximately square door 5, which may be formed from a similar material as housing 2, is secured to each open end of housing 2 in order to form an enclosed housing 2. Each door 5 and 5 may be secured to housing 2 in any suitable manner, and as shown, such manner of mounting comprises a hinge pin 23 which extends along the meeting edge of the doors 5 and 5 and housing 2 at one side of doors 5 and 5 and to which is secured a pair of mating hinge plates 22 at each of its ends. One of each pair of hinge plates 22 is secured to doors 5 and 5, and the other hinge plate 22 of each pair is secured to the housing 2 so that plates 22 may rotate over the hinge pin 23 in the well known hinge manner. In order to provide means for locking doors 5 and 5 to housing 2 at the opposite side of each door 5 and f5 and housing 2 from the hinge pin 23, a hasp 24 and a plate 240 are secured to the doors 5 and 5' and housing 2, respectively, in any suitable manner such as by riveting. Plate 240 extends through its cooperating hasp 24 and is provided with an opening 242 at its outer end through which the keeper arm of a padlock 6 may be inserted whereby unauthorized access to the housing 2 may be prevented. To further help secure each door 5 and 5' to housing 2, a plurality of overcenter spring latches 2b, which are pivotally mounted on housing 2, may be provided to engage a plurality of oppositely located latch books 21 secured to doors 5 and 5' which operate in the well known latch manner to hold the doors 5 and 5 securely to the housing 2. Inasmuch as such latch, hinge and hasp constructions are well known in the art, and do not form a part of our invention, it is not believed necessary to more particularly point out their construction or operation. Doors 5 and 5 are also provided with an integral flange 7 around their inner periphery in which a gasket 32 of any suitable material, such as rubber," may be located, so as to make doors and 5' weathertight with respect to housing 2 in conjunction with flange 4 on housing 2.

As also shown in Fig. 1, ball joint 8 is displaced toward one end of housing2 which, forthe sake of convenience, is referred to as the back of housing 2. As more clearly explained hereinafter, a power unit 200 is locatedin' the back part of housing 2, and, accordingly, thedoor' 5 at the back of housing 2 is solid in order to prevent accidental access to power unit 200. The other door 5 at the front of housing 2 is provided with a central, approximately square opening 9 which is covered by a lens 10 in orderthat light rays emitting from within housing 2, as hereinafter described, may betr'ansmitted'through lens'10. Lens 10 is located immediately behind the opening 9 and is secured to the door 5by any'suitablemeans, such as by providing a plurality of inwardly projecting lugs ILintegraI with door 5 adjacent lens 10, upon which are located. clips 12 which engage the inner surface of 'lens' 10. Clips 12 are held in this position by any. suitable means, such as machine screws 13, which pass through clips 12 and engage threaded openings-in lugs 11. If'desired, inorder to obtain a weathertight construction between the lens 10 and the opening9, a gasket 14 of any suitablematerial, such as neoprene or rubber, may be located between'the inner surface of door 5 around'the periphery of opening 9 and the outward facing side of lens 10.

In an approach lighting system, it is quite desirable that the lighting units may be movably supported in order that the light rays emanating therefrom may be directed as desired. In order to accomplish this purpose, a variety of movable supporting constructions may be employed. As shown, however, a ball joint 8 is-employed which comprises a hollow ball member 15 which may be made of any suitable material, such as aluminum, for the same reasons as given with regard to housing. 2, and which is provided with a separate outwardly extending flange member 16 fixed thereto below its horizontal centerline. It will be noted'that ball member 15is cut ca at both its top and bottom in order to provide a wiring channel therethrough, and that its lower end is provided with an integral downwardly extending hollow stem 17. Stem 17, in turn, may be'of any desired length and may' be secured in any suitable manner (not shown) to a stationary support (not shown) for the lighting unit. "Base 3 'of housing 2 is provided with an opening" 18 which .is formed to provide a spherical socket accommodating'theouter surface of ball member 15 which permits ball member 15 to' be moved in relationthereto. In order to definitely position ball member 15 to base 3,.the flange member 16 is provided with a plurality of'openings'through which extend machine bolts 19' whichthreade'dly engage openings in threaded openings in the-base 3 adjacent opening '18. It is obvious that the relative position of ball member 15 .to base 3, and, accordingly, housing 2 may easily-be varied by loosening the bolts 19 and movingvhou'sing 2 to'the desired position, then clamping ball member 15 between base 3 and flange member 16 with bolts 19.

As can be appreciated in large units of'this type, doors 5 and 5 are somewhat bulky, and in order to prevent doors 5 and 5' from swinging closed after being opened, the upper inner surface of housing 2 is provided with an integral pair of bosses 25 adjacent the lips 4-respe'ctively. Bosses 25 are provided with integral downwardly extending guide plates 26 having an opening '27thereinthrough which a guide rod'23 extends. The inner endof guide rod 28 is provided with an oflset'29 and a catch 36, 50 that when the guide rod 28 is moved outwardly frornthe housing 2 by the opening of door 5, the rod 28.will.r.ide on the lower edge of opening 27 until catch 30 engages the guide plate 26. As offset 29 will-then engage the outcriside of opening 27, anyrnovement of-door S-inthe reverse direction will cause offset 29 to :engagethe-outer side of 'door 5, rod"28 need only be lifted above'the side of opening 27, so that offset 29 clears the opening 27. In order that guide rod 28 may be activated by opening of the door 5, its outer end is flattened and secured to the inner surface of door 5 by any suitable means, such as a machine screw 33 engaging an integral boss on the inner surface of door 5.

The flash unit isalso provided with-a dish-shaped reflector 36 which may-be made from any suitable material, such as aluminum, or aluminum alloy, which may be provided with a smooth reflecting surface, and which is located within the housing 2 behind the lens 10. The outer edge of reflector 36 is provided with a small outwardly projecting flat flange 41 which is secured at various points around its outer edge by-means of machine screws (not shown) extending therethrough and engaging threaded openings in lugs 38 integral with housing 2 which project inwardly thereof behind flange 41. Housing 2 is also provided with an integral lug 39 which extends downwardly from the upper inner surface and to which is secured by any suitable means, such as machine bolts, :1 downwardly extending supporting plate 37. Plate 37 which is formed from any suitable insulating material such as a phenolic material is located in engagement with the vertex or reflector 36 and is secured thereto by any suitable means such as bolt 42 extending therethrough.

Although such a lighting unit may employ any one of various types of discharge devices, in order to obtain a high intensity light output, a krypton light 43 is preferably employed which is located within reflector 36 so as to obtain the maximum light output from the lamp 43. Such lamps 43 are provided with a main terminal at each of their ends, each of which is adapted to be energized and supported by a socket type lampholder 44. It will be noted, however, that the lampholder 44 next to the vertex of reflector 36, may be supported against the inner surface of reflector 36 by means of the bolt 42, while the opposite lampholder 44 is supported by means of a spring biased horizontally movable L-shaped support 45 to whichit may be secured in any suitable manner. Support 45 extends above the lamp 43 and is slidably supported by plate 37 by means of a bolt 46 secured to the plate 37 having a center opening therein. In order that the outer lampholder 44 may be biased to hold a lamp in operative position, a threaded stud 47 is secured at the inner end of support 45 and extends through the center opening in bolt 46 and upon which a spring 48 is slidably located. Spring 48 is slightly compressed against plate 37 by means of a split member 49 which is held upon stud 47 by means of a nut 50 threadedly engaging stud 47 and abutting against member 49. An inverted J-shaped flexible conductor member 51 havingits long arm firmly secured between the halves of split member 49 and its short arm secured to the plate 37 in any suitable manner, such as a terminal screw 52 is-provided to carry power to support 45. By this construction, it will be obvious that support 45 is biased toward the back of the housing 2 at all times to cause the lampholder 44 to firmly engage the main terminals of the lamp 43. In order to replace lamp 43, support 45 need only be pulled toward the front of the housing 2 thereby causing the front lampholder 44 to be separated from the lamp 43, and then the lamp is freed for removal. A high voltage terminal or ignition electrode 79 is provided centrally at one side of lamp 43 which extends laterally and beyond the envelope of lamp 43 in order that an ignition circuit 100, as subsequently described may be secured thereto in any suitable manner, such as by a solderless connector.

Referring to Figs. 2 and 5, wherein a blaze unit is shown, it will be noted that the housing 2 is identical in all-respects to the housing already discussed with relation to the flash unit, and, accordingly, like reference numerals have been used. The blaze unitis adapted, however, to utilize a plurality of elongated discharge-devices, such as gaseous tubes 60, which are arranged horizontally one above the other behind the lens and supported by any suitable socket type lamp-holding means 270. As shown in Figs. 2 and 5, it will be noted that each lamp 60 is located adjacent the vertex of a trough-shaped reflector 271. Reflectors 271 are secured at their vertices by any suitable means, such as machine screws (not shown) to an insulating plate 54 which, in turn, is secured at each of its ends by any suitable means, such as bolts 55, to inwardly projecting lugs 53 integral with the housing 2. In order to provide for rigidity for the reflector 56 and in order that they may retain proper spacing with relation to each other, each reflector 271 is provided with a flat outwardly projecting flange 272 at each of its edges which overlaps the corresponding flange 272 of the adjacent reflector 271. Reflectors 271 may be formed of any suitable material such as aluminum or an aluminum alloy, which is capable of being processed to obtain a high reflecting surface. Also, in order to insulate the reflectors 271, from the housing 2, plate 54 is formed of any suitable insulating material, such as a phenolic insulating material.

In view of the fact that lamps 60 differ from lamp 43, a power unit 210 having different components than power unit 200 is located within the housing 2. Although not shown in the wiring diagrams, each housing 2 is provided with a door switch 59 adjacent the inner lower edge of each door 5 and 5 so that when any door 5 or 5' is open, the power supply to the power unit is interrupted.

As has been indicated, the power unit 200 for the flash unit is located within the housing 2 and comprises that part of the circuit shown in Fig. 4, which is bounded by the dot-dash outline. As shown, the electrical power for operating the flash unit is supplied from any suitable three-wire source 203 of alternating current. It should be noted, however, that if desired an individual unit may be operated from any suitable two-wire source rather than the three-wire source; however, when a plurality of such units are operated from a common source, a threewire source is preferred in order to obtain a balancing of the load. Source 203 comprises two main power conductors 61 and 62 and a neutral conductor 63. The power unit 200 is selectively controlled as hereinafter described by means of a flash selector 202, ignition control 201, and a switch S1, which components may, if desired, be mounted within the housing 2 so as to be accessible from the outside of housing 2, whereby a flash unit can be controlled at its location. In keeping, however, with an approach lighting system, wherein it is desired to have a central control area, such controls are remotely located so that a plurality of light units may be operated from these controls at a central location and having individual control cables extending to the flash units.

As shown, the flash selector 202 comprises a rotary drum switch which is utilized to control various sections of the power unit 200; however, other types of standard control devices could be utilized for such purposes. Selector 202 is operable from an off-position through positions 1, 2, 3, 4 and 5, of which position No. 2 is the low intensity setting, position No. 5 is the high intensity setting and positions 1, 3 and 4 are provided to accomplish certain control functions as hereinafter described. The ignition control 201 is utilized to effect a flash operation of the flash unit at timed intervals, and, accordingly, a precision timer (not shown) is contained therein to accomplish such purpose. For a more detailed description of such a timer the above-identified copending application is again referred to.

Power unit 200 comprises a pair of condensers or condenser banks CF-l and CF-Z, with condenser CF-l being connected in parallel across the main end electrodes 80 and S1 of the lamp 43. Condenser CF-2 is selectively connectibleinvparallel: with condenser CF-1 by means of a reIay 84. Condensers CF-l and CF2 are alternately charged,'and then discharged through the lamp 43 when its ignition electrode 79 is energized in response to the ignition control 201 as hereinafter explained. In addition to the condenser banks, the power unit 200 comprises a plurality of control relays 82, 83 and 84, a filament transformer TF2, a power transformer TF1, a pair of rectifier tubes 85 and86, a pair of resistors RFI and RF2, and a pair of potentiometers 87 and 88. The electrical energy for operating the lamp 43 as well as the control relays of the power unit is obtained from the supply circuit 203. Filament transformer TF2 has its secondary winding 89 connected to the filaments of the rectifier tubes in a well-known manner and the secondary winding 90 of the power transformer TF1 is connected to the plates of the tubes. The charging circuit for the condensers extends from the middle tap 91 on the secondary winding 90, through conductor 92, condenser CFl, conductors 93 and 94, contact members 84a, conductor 95, potentiometer 87 andresistor RF2 to the middle tap of the secondary winding 89 of the filament transformer TF2.

It will be noted in this instance that this is the charging circuit for both condensers CF-ll and CF-2 in parallel which'is effective when relay 84 is deenergized as shown. In this position, contact 84b connects condenser CF2 in parallel with CFl. Contact members 84a when closed, as shown, shunt the potentiometer 88 and resistor RF from the charging circuit. This provides for increasing the charging current for the maximum capacitor connection. It will be apparent that when relay 04 opens its contact members, condenser CF2 will be disconnected and the potentiometer 88 and resistor RFI rendered effective so as to increase the resistance of the charging circuit for the lower capacitor connection. As will be described hereinafter, the single capacitor CFl is used for low intensity flashing operation and both capacitors for high intensity flashing operation.

Relay 83 functions to control the effectiveness of the discharge resistor RF3 connected across the capacitors, while relay 82 functions to render the ignition circuit controlled by the ignition control 201 effective. This circuit is closed by contact members 82a. Relay 82 also functions to energize the primary winding 96 of the power transformer TF1 through its contact members 82b.

Reference has been made to the operation of the lamps 43 by energizing their ignition electrodes 79. In order to provide a high frequency, high-voltage ignition voltage which may be impressed on the ignition electrode in response to the operation of the ignition control 201, each power unit also embodies an ignition circuit 100 which comprises a transformer 244 connected across supply conductors 6263 for inducing a high voltage in its secondary. Such high voltage is utilized to charge a condenser 246 connected across the secondary until such charge is suflicient to cause a spark gap 248, connected in series with the secondary of transformer 244, to break down and conduct, thereby producing a surge through the primary of another transformer 250 connected in series with spark gap 248 and the secondary of transformer 244. Such surge through the primary of transformer 250 causes a higher voltage to be generated in the high-voltage secondary winding 101 of transformer 250 which is connected to the ignition electrode 79 as previously indicated and to ground. The operation of the power unit 200 is such that when lamp 43 is subjected to the proper operating voltage by the condensers and, when the ignition electrode 79 is energized, the lamp 43 is caused to discharge and flash. With such a lamp 43, as described, it is necessary to energize the ignition electrode 79 for each flash operation of the lamp.

In order to operate the flash unit, a switch S-1 must initially be closed which establishes a circuit for energizing the primary winding of the filament transformer TF2. This circuit extends from conductor 63 through switch 7 8-1; primary Winding of TF 2, conductor 133e,- and-conductor133 to the distribution conductor 62.' If-desired, door switches 59 maybe connected'in series with' switch 8-1, to 'prevent energ'izationof power""unit 200"when either door is open. As shown,all relays are in the deenergized position, and if a low-flash op'eration is-desired, the flash selector-switch 65 is actuated from' its-off position through the No. l-position to it's'No. 2 low position. On the intermediate No. l position,-"the control conductor for relay 84 isenergized through a circuit from ground conductor 63, through'contact members 134 and 135 of the selector switch 202, which are bridged by the connected movable segments l36'and 137, conductor 140, operating coil of relay =84 todistribution conductor 62. This effects the-opening of relay 84 50 as td'disconnect condenser CF2 and increase the'resistance'of the charging circuit for condenser -CF1 by rendering potentiometer 88-and its associated resistor R-Fl effective, as described hereinbefore.

On position No. 2 of the -selector'switch 202,- which is the low intensity fiash'position,an energizing circuit for relays 82 and 83 of the power supply uni't-isestablished. Thiscircuit extends from conductor 63 *through-contact members 134 and 143 of the selector switch 202, which are bridged by the connected movable segments 136 and 141, conductor 144, and operating coils ofrelays' 82 and 83 in parallel to distributionconductor-'62.' Relay 82 closes to energize the primary 96 of power transformer TF1 through its contact members 8212 and also closes the ignition circuit referred to hereinafter'at contact members 82a. Relay 83 operates to disconnect the discharge resistor R1 3 from the condenser circuit at cont-act membens 83a. It will, thus, be apparent that theunitis'now ready for operation on low flash.

Assuming that it is desired to operate 'theflash-units on high flash operation, the selector switch may be actuated through positions Nos. 3 and 4 to 'thehigh intensity position No. 5. On position No. 3;all of the relays which have been energized on the low intensity flashing operation with the exception of 'relay-84'aredeenergized. On position No. 4, relay'84 is also de'energized and condenser CF2 is then-connected in parallel with CFl, so as to increase the available capacity, and the charging circuit is recalibrated by shunting thepotentiometer 88 and resistorRFl. This provides for subjecting the lamp 43 to a higher operating-discharge'current. On the high intensity position-No. 5; relays" 82 and 83 areagain energized through'the segment T45 of the selector switch 2G2, the relay 84 is deener'gized as at positions No. 4 and 5. and 83 again perform-the-same functions BS'bEfOIB. Relay 32 closes the ignition circuit at contact'members 82a and energizes the power transformer TFI'at contact members 32b. Relay 83 'disconnectsthe'=discharge=resistor RPS at 83a.

In order to obtain ignition of lamps -43, electrode 79 is controlled through'the ignition control- 201 'whenthe elector switch is at either position No. 2 or No. 5. Electrode 79 is energized through ignitionwircuit 100, which, in turn, is energized from conductor-63, by conductor 148b, control 201, conductor 148a, contacts 82a, the primary of transformer 244,- conductor 133 to'supply conductor 62. The exact method of timing of-ignition control 201 is unimportant from the stan'dpoint-"of a single flash unit; however, when a larger number of units are energized and a flash sequence is desired, such ignition control'is of great importance and accordingly for such controls the above-identified case should-be consulted. "Such flash units will'be operable at their maximum high intensity as long as selector switch 202 rernains on position No. 5 and in accordance with' the operation of;ignition control 201.

- Referring again to the condenser char'ging -circuit; it will'be noted that rectifier tubeS SS-a'nd 86 are connected so that thetubesconduct'on alternate half cycles so as Upon energization, relays-82 to e'on'stitute a full-wave rectifier. Thus, over a=period of time ailargejcharge will be placed up'on the capacitors, whichis diseharged'across the'electro'des"80 and 810i: 'lam t43 when lamp 43 is triggered by' ener'gizi'ng' 'its third electrode .79. Whensuch' triggering occurs; the voltage across"the-condenser falls'tothe voltage value across the plate and grid of the rectifier tube then'conducting-Which is insufiicient to maintain a discharge across the lamp '43. -'By utilizing rectifier tubes '85 and 86 SO 'ihBt tl'lC rectifiedhalf-wave voltage drops 'to substantially zero within' one-half cyclcafter triggering, applicant isable'to insure that only a flash discharge occurs across lamp'43. Further, when a'plurality'of such'lighting-units are'used, separate rectifier'tubes '85 and'86for charging condensers CF-l and CF-2 are located in-each lighting unit. As'rectifier tubes *and 86 conduct'in one direction' only, feed back from the charged condensers (BF-Tand CF-Zih oneunit is prevented and one u'nit'will not have any-electrical effect upon the other. It isgof course, obvious that the ignition of lamp 43-must be timed so'a's'tooccur after the condenser has had sufficie'nt time'to become charged.

As has also been indicated, the power circuit 210 for the 'blazeunit is locat'ed within its'housing 2 and comprises the part of the circuit shown in Fig. 6, which is bounded by the dot-dash outline. As before, the electrical po'wer foroperating this'unit is supplied from any suitable source 214 such as a three-wire system having two main1conductors'56 and 58 and a neutral conductor 57. MI]? desired, a two-wire system could be employed. The power unit 210 is selectively controlled as hereinafter' des'c ribedby means of a selector 212, ignition control- 211, and a switch S-2, which components may be mounted'inthesame-manner as the 'similar components previously described.

shown, selector 212 comprises a rotary drum switch which'zis utilized to control various sections of the power unit 210; howeverfiothe'r types of standard control device could be-=utilized-'-forsuch'purposes. Lamps 60 are adapted to'beioperated'as either flashing units or steady burning, i-.'.e.,'blaze"units, and, accordingly, selector 212 provides a controlfor bothtypes of operation. Selector 212 isuoperable for'fiash operation from an off position through positions 1, 2, 3, 4,'a'nd' 5 of which position No. 2' is the 'low "intensity setting, position No. 5 is the high intensity -setting',-and positions No. 1, No. 3, and No: 4-are provided to accomplish certain control functions. In"the.opposite direction, selector 212 is operable through positions' Nos. 1 to 4 which is the blaze or steady operating-direction. Position No. 2 is the low intensity positionyNo. 3 the medium intensity, No. 4 the high intensity, and'No. 1' is'for switching purposes. The ignition-control 211" is utilized to'energize lamp's 60 and effect a flash {operationthereof in a timed sequence, and, accordingly, a precision timer (not shown) is contained therein to accomplish such purposes.

The power'unit 210' functions in generally' 'the same wayas apower 'unit 200 described in connection with the flash unitexcept that in this instance the lamps 60 arenoperated in 'two different ways;"=namely,' flash and steady. lnsofaras' the flash operation is concerned, the elements-and -their"man'ner of operation are generally the same. As-shown, thesix lamps 60-are connected in series" circuit-relationjand each-lamp-is provided with a cutout device 108 connected in parallel therewith to-provide a s'htint con-nection for the lamp in the event of failure thereof. In general, each unit 210 comprises a pair of rectifier tubes 109 and 110, aplurality of control relays-1 11, 1'12; 113, 114, "116 and 117, a power transf'o'rmer'TBl; a filament transformer TB2, potentiometers 118 and 119, and resistors" RBI," RB2, R33, and R84. As 'in the case of power -unit 200, the plates of tubes 109 and are 'connected to the secondary winding of the ower transformer 'TB1, and the filaments to the secondary win'ding ot the filament transformer TB2. 'The charging circuit for the condensers oncondenser banks CB1 and CB2 extends from,a-;middle tap 1211 on the secondary winding of power transformer TB1 through contact members 1160, either condenser CB1 alone, or in parallel with CB2, depending upon the position of the relays 116 and 117, and either through both potentiometers 118 and 119,,and resistors RS1 and R32 in series or potentiometer 119 and resistor R131 alone, depending upon the position of relay 117, to the middle tap 121 on the secondary winding of power transformer TB2.

As will be explained more in detail hereinafter, relay 116 is energized whenthe lamps, 60 are being operated as flash lamps and closes the'charging circuit at contact members 1160 and condenser CB1 ,is effective. When relay 117 is deenergized, as shown, it connects the second condenser CB2 to the charging circuit in parallel with CB1 through contact members 1170. With contact members. 117 b closed and contact members 116g of relay 116 also closed, the potentiometer 118and its associated resistor RBZ are shunted outof :;the charging circuit, so as todecrease the resistancethereof. When relay 117 is energized, condenser CB2 is disconnected, and the potentiometer 118 and resistor RB2 rendered effective to increase the resistance of the charging circuit on low intensity flash operation.

When the lamps 60 are operated assteady units, the condensers and their associated charging circuits are ineffective as relay 116 is deenergized. In this instance, the lamps are connected directly across the secondary winding of the power transformer TB1 through contact members 116a and 116 of the relay 116, which is the main control relay. When relay 116 is energized, this connection is interrupted, and the lamps are connected across the capacitors through contact members 116b. The charging circuit for the capacitors is'closed through contact members 1160 as explained hereinbefore. Contact members 116d and 116e control the connection of the discharge resistors RB3 and RB4 to the condensers. Relay 116 is also provided with other contact members 116h which close the ignition circuit or connection 123 to the lamps 60.

As in the case of the flash unit, each blaze unit embodies an ignition circuit having a transformer 124 connected across the supply conductors 57-58 for inducing a high voltage on a condenser'146 connected across its secondary. A spark gap 149 and the primary of another transformer 125 are connected across condenser 146 to obtain a high voltage surge through transformer 125 as previously discussed. The secondary of transformer 125 is connected between ground and the ignition connection 123 through contact members 116k; This ignition connection goes to the midpoint of the series-connected lamps, as shown.

When relay 116 is deenergized; as shown, the lamps 60 are connected for steady operation across the secondary winding 128 of the power transformer TB1, and its primary winding 129 is selectively connectible to the conductors 57 and 58 of the distribution circuit in a number of diiferent ways by the operation of relays 112, 113, and 114. The final connection to the distribution circuit is made through contact members 111b of relay 111. This is the main energizing relay for the power supply unit. The contact members of the other control relays 112, 113, and 114 are so arranged and interconnected that, when relay 112 is energized and closed, as it is throughout the steady operation, relays 113 and 114 function to provide the necessary connections for the primary winding 129to subject the lamps to the desired operating Voltages. When relay 113 is closed, the primary winding 129 of power transformer TB1 is connected from conductor 57 and in series with the lower portion of reactor winding R, tap connection 131, and contact members 113b, 112a, and 111b. to conductor 58.. This provides the necessary secondary voltage for operating the lamps on high steady operation. H 1

For the medium: steady operation relay 113 is open and relay 114 closed. This connects the primary winding 129 through the entire winding of reactor R and contact members 11 1b, 113a, 112a, and 111b. This provides the intermediate secondary voltage for medium steady operation. For low steady operation, relays 113 and 114 are both open, and the primary winding 129 is connected directly to conductors 57 and 58 through resistor R7 and contact members 114a, 113a, 112a, and 111b. This provides the necessary low secondary voltage. Power unit 216 also includes a third transformer TB3 and a condenser CB3 which is rendered effective for power factor correction when both relays 112 and 113 are energized and closed on high steady operation. 7 p

The operation of the blaze unit for flashing operation is generally the same as for the flash unit. When switch 8-2 is closed, the primary of thefilament transformer TB2 is energized from conductor 57 to distribution condoctor 58. Door switches 59 may be connected in series with the primaries of transformers TB1 and TB2, to prevent energization of power unit 210 when either door 5 is open. Fig. 6 illustrates the condition of the circuit with the blaze selector switch 212 in the off position. It will be apparent that when the selector switch 212 is in the oil? position, a circuit is established which extends from conductor 57 through stationary contact members 153 and 155 bridged by the connected segments 150 and 151 to conductor 154, whereby an operating circuit for relay 112 is established to distribution conductor 58.

When relay 112 is closed, it performs a number of functions; at contact members 112b, it, opens the power connection to the tap of transformer TB1; it closes its contact members 11211 to connect the entire primary winding 129 of power transformer TB1 to conductor 58;

at contact members 112e, it partially closes the circuit to transformer TB3 from conductor 57. On flash position No. l of the selector switch 212, the operating circuit for relay 112 is deenergized and relay 112 opens. With relay 112 open, contacts 112d are closed, and the main control relay 116, which functions to set up the necessary connections to the lamps for flash operation, is energized from conductor 58, through contacts 112d, to conductor 57. Relay 116 at contacts 116b and 116c establishes the charging circuit for the condensers and connects the lamps across the condensers. Contact members 116a and 116 are opened so as to disconnect the lamps from the full secondary winding of the transformer TB1 which is the blaze or steady connection. Contact members 116e open to disconnect the condenser discharge resistors RB?) and RB4. Contact members 116g are also closed. It should be noted that relay 116 stays closed during the entire flashing operation.

On position No. 1, relay 117 is energized from conductor 57, segment which is internally connected to segment 159, through stationary contact member 158, and conductor 161 to conductor 58. Relay 117 opens to disconnect condenser CB2 at contact members 117a and to increase the resistance of the charging circuit by opening contact members 117b to render potentiometer 118 and resistance RB2 effective.

When the selector 212 is actuated to the low flash position No. 2, relay 111 is energized from conductor 57, segment 15%) of switch 212 which is internally connected to segment 163, through stationary contact element 167, and conductor 173 to conductor 58. Relay 112 continues to be deenergized as previously described. Upon the operation of relay 111, the ignition circuit is closed at contact members 111a; at contact members 111b, the energizing circuit for the power transformer TB1 is completed. The circuit extends from distribution conductor 58, through contact members 111b, 112b, tap 130, and a part of primary 129 to conductor 57. The power unit is now energized. When the ignition control 211 is operated, the blaze units are all being flashed at low intensity. The previous remarks regarding the igni- -tion' control 201 of' the flash 'unit are equallypertinent here and need not berepeated.

- If it is desired to flash the blaze units at high intensity, the selector switch 2-12 maybe operated through positions Nos. 3 and 4 to'the high -intensity'position No. 5. 'At posi- -tion No.-3;' relay"111 is deenerg'izedybut relay 1'17 18 still held energized.

Whenthe-selector switch "212 is operated to positlon No. 4, relay-1'17 isalso dee'nergized, and capacitor CB2 isconnected ihto the circuit, andthe relay also decreases 'the resistance of the-charging circuitby shunting potenti- 211 is utilized, as before, to initiate the high intensity discharge.

When it is desired to operate the blazeunits to produce a 'steadylight, the'selectorswitch212 is'returned to the off position, and the relay112 is again energized through the contact-segment 151 and' closed. When relay 112 closes, it deenergizes through contacts 112d the main control-relay 116 which, at its-normally closed contact members 116a-and '116f, connects "the lamps 60 to the secondary winding of the power transformer TBl for steadyoperation. In'other words, the lamps are connected directly across the full secondary winding of the transformer. Other contact'members 116b, 116a, and 116g of' relay 116 disconnect the lamps from the condenser and charging circuit. -It is to be noted that relay 112 remains energized and relay'116remains 'deenergized throughout the steadyoperation, so'as to maintain these connections.

At position No. l in the-blaze or steady direction of operation of the selector switch 212, relay 117 is again energized fromconductor 57, segment 150 of switch 212 which is internally connected tosegment 170, through stationary contact member 158, through conductor 161 to conductor 58 which opens to disconnect condenser CB2 from the charging circuit.

On position No. 2, which is the low intensity steady position, relay 111 is energized from conductor 57, segment 150 of switch 212 which is internally connected to segment 174, through'stationary contact member 167 of switch '212 'through' conductor 173 to conductor 58. Relay 111 remains'energized throughout'the blaze operation and at contact members 1111; connects the primary winding-129 of power transformer TB1 to the distribution circuit. In this instance, 'since' relay 112 is closed and relays '113-and 114 open, this primary winding is connected to conductors 57 and 58 through contact'members 111b, 112a, 113a, -1-1-4a,'and resistor R7. This provides the necessary-secondary*operating voltage for low intensity steady-operation.

When the selector switch 212 ism'oved to position No. 3, which is 'the medium-intensity steady'position, all of the relays which were-operated remain closed and, in addition, relay 114 is ene'rgized' from conductor 57,- segment-150 of switch 212 which is internally connected to segment 180, through stationary contact member 179 and conductor 182 to conductor 58. When contact members 114a are opened and 1141) closed, the primary winding 129 of transformers TBl is-connected to the distribution conductors 57 and 58 through the full winding of reactor R. This provides the necessary secondary voltage for medium intensity steady operation.

-When the selector switch 212 is'zoperated to position No. 4, which is the high intensity steady position, the same relays remainoperated, except-that relay114 is deenergized, and relay 113 is energized from conductor 57, segment of switch 212wliich is lnternally 'conne'cted to segment'185, through stationary'contact member 184, and conductor187 to 'conductor'58." When relay 113 now closes, the primary winding 129 of transformer TBl is connected to the source through the tap connection 131 of reactor R. This establishes the correct secondary voltage for the highintensity steady operation. At the same time, relay 113 through its contact members 1130 completes the energizing circuit'for transformer TBS which was partially closed through contact members 112c. This renders the condenser CB3 eflective for power factor correction.

' While separate flashing operations of the flash and blaze units have been described, it will 'be'apparent that a plurality' of "these units marbe-operated in unison, as described in the'above-identified' case. In view of the foregoing detaileddescriptionof a preferred'embodiment of my-invention, it willbe apparent that I have provided a novel type-of lighting 'systemfor facilitating the visual landing of'aircraft under'all 'weather'conditions. The most important aspect of this invention is in the individual lighting units and'in the useof individual power supply units'in *each'type of unit which is entirely separated from similar -units,'whereby a flash of light may be obtained.

While a specific embodiment of my invention has been described, it is to be understood that the principles of the invention may bepracticed-inother ways. Thus, if desired, only single flash intensities could easily be obtained by simplifying-the control components. Also, in the blaze unit,- the'flashing operation could easily be eliminated. Accordingly-the-particular embodiment described is to be considered as-illustrative only.

I claim as my invention:

1. A light unit comprising a housing having mounted therein a'reflector, lamp supporting means mounted in said reflector adapted-to support a lamp having a pair of main terminals and a third ignition terminal, and a power supply unit'mountedin said housing comprising a first circuit connected-to :capacitive means for charging the same including acondenser -discharge"resistance, said capacitive means being connected to the main terminals of'said lampsupporting means; a" second circuit-com nected to said third terminal, afirst'relay means for varying the capacitance of said capacitor means, a second relay means for disconnectingsaiddischarge resistance from said=first circuit, and a'thirdrelay means for energizing said first and-second circuits from a source of power for causing a discharge across a lamp when inserted in said lamp supportingmeans.

2. A lightunit comprising a housing having mounted therein a reflector,"-lamp supporting -means mounted in said reflector adapted to su'pport a lamp-having a pair of main terminals'and a=third-ignitionterminal, and a'power supply unit mounted in said "housing comprising a first circuit connected tocapacitiverneans for charging the same, means' for electrically connecting said capacitive means to lamp supporting means to discharge across said mainterminals, a-second"-'circuit connected'to' said third terminal; a firstrelay means for-varying the capacitance of said capactive meangand a 'seco'nd'relay means for energizingsaidfi'rst and second circuits from a source of power-forcausing a 'di'scharge across a lamp when inserted in said lamp supporting means.

3."A light "unit comprising a'housing having mounted therein a'refiector, lamp*-"supportin'g' means' mounted in said reflector adaptedto support a' lamp having a pair of main terminals "and a' thirdignition" terminal, and a power supplyunit mounted insaid h'ousingcomprising a first'circuit connected-to capacitive means for charging the s'ame including 'a'c'onde'nser discharge resistance, said capacitive means "being connected to the main terminals of -said lamp}supporting' rneans, asecond circuit connected to said' third-terhtinal; a "firstrelay means 'for varying the capacitance of said capacitor means,- a' secnd relay means for disconnecting said dis-chargeresistance from said first circuit, and athird relay means for energizing said first and second circuits from a source of power for causing a discharge across a lamp when inserted in said lamp supporting means, and said second and third relays being electrically connected together so as to be operable simultaneously.

4. A light unit comprising a housing having mounted therein at least one lamp supporting means which is adapted to support a lamp, a power supply unit mounted in said housing comprising a plurality of energy storing means at least one of which is connected to said lamp supporting means, switching means for selectably connecting another of said energy storing means to said lamp supporting means, triggering means connected to said lamp for causing a discharge of said energy storing means connected to said lamp supporting means to occur across a lamp when mounted in said lamp supporting means, and means connected to said energy storing means for causing the voltage of said energy storing means to drop to a value below the voltage which will sustain a discharge across said lamp after said energy storing means has been discharged.

5. A light unit comprising a housing having an opening therein, a plurality of elongated reflectors contiguously mounted within said housing behind said opening in a plane approximately parallel thereto, lamp supporting means mounted within said housing to support a lamp in each of said reflectors, respectively, means for electrically connecting said lamp supporting means to each other, a power supply unit mounted in said housing comprising a first energy storing means connected across said lamp supporting means, a second energy storing means, switching means for connecting said second energy storing means across said lamp supporting means, means adapted to be connected to said lamp for causing a discharge of said energy storing means across a plurality of lamps when mounted in said lamp supporting means, and means connected to said energy storing means for causing the voltage therein to drop to a value below the voltage which will sustain a discharge across said lamps after said energy storing means has been discharged.

6. A light unit comprising a housing having at least one reflector mounted therein, lamp supporting means mounted in said housing to support a lamp in fixed relationship with respect to said reflector, a power supply unit mounted in said housing comprising a transformer having its secondary connected across said lamp supporting means, said transformer having a primary for controlling the energization of said secondary and adapted to be connected to an alternating current source, a plurality of impedances connected in parallel in the connection of said source to said primary, and switching means in each of said parallel connection so that the excitation level of said primary may be selectively varied.

7. A light unit comprising a housing having at least one reflector mounted therein, lamp supporting means mounted in said housing so as to be adapted to support a lamp within said reflector, a power supply unit mounted in said housing comprising a transformer having its secondary connected across said lamp supporting means, said transformer having a primary which is adapted to be connected to a source of power for controlling the energization of said secondary, a parallel connected resistor and reactor connected in series with said primary for controlling the excitation thereof, and switching means in each branch of said parallel circuit so that the excitation of said primary may be varied.

8. A light unit comprising a tubular housing having movable covers for covering each of its ends, and enlarged dish-shaped reflector, means on said housing engageable with said reflector for supporting said reflector with its Open end facing one of said ends of said housing and so that its apex extendsinwardly of said housing, an insulating support extending inwardly from one inner surface of said housing so as to engage the outer side of said apex, a rigid first lamp holding means extending through said apex portion of said reflector and said support, a second lamp holding means movably secured to said support which extends inwardly of said reflector so as to be spaced from said first lamp holding means in a manner to support a gaseous discharge device therebetween, means connected to said support for biasing said second lamp holding means toward said first lamp holding means, a power supply unit secured to the inner surface of said housing so as to be located at least in part between said reflector and the last-mentioned inner surface, and means for electrically connecting said power supply unit to said lamp holding means.

'9. A light unit comprising a housing having an opening therein, at least one reflector mounted within said housing behind said opening, lamp supporting means mounted in said housing to support a lamp in fixed relationship with respect to said reflector, a power supply unit mounted in said housing having two control circuits for controlling energization of said lamp supporting means, a first switching means for selecting either of said control circuits so that said control circuits are adapted to be energized from a source of electrical energy, one of said control circuits comprising a plurality of energy storing means at least one of which is connected to said lamp supporting means, a second switching means for selectably connecting another of said energy storing means to said lamp supporting means, means connected to said lamp supporting means for causing a discharge of said energy storing means, means connected to said energy storing means for causing the voltage therein to drop to a value below the voltage which will sustain a discharge across said lamps, the other of said control circuits comprising a transformer having a secondary connected across said lamp supporting means, said transformer having a primary for controlling the energization of said secondary, a plurality of control means connected to said primary for varying the excitation thereof, and a third switching means connected to each of said control means so that the excitation of said primary may be varied.

10. A self-contained light unit for use at airports and the like as an aid to airplane landing operations and the like, comprising, a reflector housing having a transparent front cover, a reflector mounted in said housing behind the front cover, lamp supporting means adapted to support a high-intensity discharge lamp having main terminals and an igniter terminal mounted within the reflector, a power supply unit mounted within the housing and electrically connected to the lamp supporting means and said igniter terminal, said power supply unit having input terminals adapted to be energized from an alternating current power source and including means for converting such alternating current to a pulsating direct current, energy storing means supplied with said pulsating current, means connecting said energy storing means to said lamp supporting means so that said energy storing means can discharge across the main terminals of said lamp, and means including a separate and direct connection of said source to the igniter terminal of said lamp supporting means including voltage step-up means for supplying a relatively high voltage to said igniter terminal.

11. A self-contained light unit for use at airports and the like as an aid to airplane landing operations and the like, comprising, a reflector housing having a transparent front cover, a reflector mounted in said housing behind the front cover, lamp supporting means adapted to support a high-intensity discharge lamp having main terminals and an igniter terminal mounted within the reflector, a power supply unit mounted within the housing and electrically connected to the lamp supporting means and said igniter terminal, said power supply unit having input 15 terminals adapted to be energized from analternating current power source and including means for converting such alternating current to a pulsating direct current, energy storing means'supplied with said pulsating current, means connecting said energy storing means'tosaid lamp supporting means so thatsaid energy storingmeans can-discharge across the main terminals of =said lamp, means including a separate and direct-connectionofsaid source to theigniter terminal of said lamp supporting means including voltage step-up means for-supplying a relatively high voltage to said igniter terminal, and separate relay-means in the circuits to said main and igniter "1'16 terminal'means, respectively, 'and individual control sup ply conductors on saidrelays.

"' References-Cited in the file of this patent UNITED STATES PATENTS 1,318,062 Englund et al- Oct. 7, 1919 2,090,989 =Van'Deventer-et a1. Aug. 24, 1937 2,478,908 -Egerton Aug. 16, 1949 2,531,337 Knapp Nov. 21, 1950 2,602,850 Cline July 8,1952 

